1. Field
Aspects of the present disclosure relate generally to wireless communication and, more particularly, to antenna switching in a wireless terminal.
2. Background
A wireless terminal, for example, a mobile phone, may include multiple antennas. The communication channels to and from the antennas can vary greatly. For example, when a user holds a mobile phone, one antenna may be blocked by the user's band while another antenna is substantially open. When the mobile phone uses the blocked antenna for communications, there may be, for example, a 10-30 dB attenuation relative to when the unblocked antenna is used. Thus, a wireless terminal may improve performance by switching the antenna that is used away from a blocked antenna. A wireless terminal may also provide concurrent communications for two protocols. The communication channels for the protocols may differ (for example, with proximity to respective base stations) in such a way that one allocation of antennas provides reliable communication for both protocols but when the antennas are switched, reliable communication for one of the protocols is not achieved.
Antenna switching can be performed using radio frequency (RF) switches. The use of RF switches causes an insertion loss, for example, 0.5 dB on signals that pass through the RF switches. RF switches can also impair signals in other ways, for example, nonlinearities and intermodulation. Additionally, providing the RF switch can be expensive and occupy valuable physical space in a wireless terminal.